In display devices represented by liquid crystal display devices, the performance, such as luminance, resolution, and a color gamut, is rapidly progressing. Additionally, in proportion to the progress in the performance, display devices assuming the outdoor use, such as personal digital assistants and car navigation systems, are increasing.
In environments such as an outdoor environment with strong sunlight, there are cases where display devices are observed through sunglasses (hereinafter referred to as “the polarized sunglasses”) having a polarizing function in order to reduce the glare.
When a display device includes a polarization plate, there is a problem (hereinafter referred to as “the blackout”) that a screen becomes dark and hard to see when the absorption axis of polarization of the display device becomes orthogonal to the absorption axis of polarization of the polarized sunglasses.
In order to solve the above-mentioned problem, the means of PTL1 has been proposed.